Funds are requested to support a small, informal symposium entitled "Cerebrospinal Fluid (CSF) and the Brain" to be held September 11-13, 1974 in Bar Harbor, Maine. The purpose of the symposium is to bring together a number of outstanding research scientists and clinicians to discuss recent developments relating to the fluid environment of the central nervous system. There will be five sessions: (1) Comparative, Developmental and Pathological Aspects of CSF and Brain-Barrier Systems; (2) Physiology of the Choroid Plexus; (3) Physiology of the Blood-Brain Barrier: (4) CSF-Brain Exchange I; and, (5) CSF-Brain Exchange II. A number of formal presentations are planned with sufficient time for informal discussion. The formal presentations will be published as a book by Academic Press.